It is already well known that a high level of glycosylated hemoglobin in human blood is a reliable indication of a blood abnormality such as in the case of a diabetic. Because the glycosylated hemoglobin level of blood at a given point in time represents a time-averaged glucose level of the blood, determination of the glycosylated hemoglobin level of a patient's blood is a more reliable indication of the average glucose level of the patient's blood over a period of time than is afforded by determination of the glucose level itself. That is, the glycosylated hemoglobin level of a patient's blood at the time a sample is taken is much less dependent on the diet of the patient immediately prior to the sample taking than is the glucose level of the blood. Hence, considerable work has been done in recent years on methods for accurately determining the amount of glycosylated hemoglobin in blood.
At present, the most commonly used method involves separation of the glycosylated hemoglobin fraction from the other hemoglobin fractions in microcolumns of ion exchange resin with subsequent measurement, spectrophotometrically, of the amount of the adsorbed fraction constituting the glycosylated hemoglobin. This method has a number of disadvantages perhaps the chief of which is that separation of the fractions is highly temperature dependent thereby requiring meticulous temperature control or other cumbersome corrections based on empirical factors and data.
It has also been proposed to accomplish the separation by electrophoresis but the difficulty here has been that of attaining a good electrophoretic separation of the glycosylated hemoglobin fraction from the non-glycosylated hemoglobin fraction--this because the fractions have very similar mobilities. In the one electrophoretic technique which is known to have come into commercial use in this regard; the separation attained is adequate; however, the technique is expensive in that it involves the use of a specially prepared agar medium including a closely controlled concentration of sulphate moieties and with the separation involving endosmosis.
The present invention provides a reliable and relatively inexpensive method for attaining electrophoretically an excellent separation of the glycosylated hemoglobin from the other hemoglobin fractions.